Key Points on IGS Contribution to ITRF2020 Updates
Discover the essential details of the IGS contribution to ITRF2020 updates, including the inter-technique link, precise polar motion estimates, plate motion models, and more. Regular yearly updates of ITRF2020 and transformation parameters from ITRF2020 to past ITRFs are also highlighted. Explore the motivation, specifications, and significance of these contributions in this comprehensive overview.
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ITRF2020 Updates and the IGS Contribution Zuheir Altamimi Paul Rebischung, Xavier Collilieux, Laurent M tivier, Kristel Chanard, Julien Barn oud IGN-IPGP, France Altamimi et al., IGS Workshop 2024, Bern, Switzerland
Key Points IGS Contribution to the ITRF is fundamental Regular (yearly) updates of ITRF2020 Motivation ITRF2020 Update Specifications Some Early/Preliminary Results Conclusion Altamimi et al., IGS Workshop 2024, Bern, Switzerland
The IGS specific contribution to the ITRF 1. Ensures the Inter-Technique link : 1. Connecting the three other techniques within the ITRF combination 2. ==> Reinforcing the ITRF definition (origin, scale & orientation) 2. Provides the most precise Polar Motion estimates 3. Determination of Post-Seismic Deformation Models 4. Significant contribution to the ITRFyy Plate Motion Models 5. ITRF Access & densification through the IGS Products Altamimi et al., IGS Workshop 2024, Bern, Switzerland
Regular (yearly) updates of ITRF2020 ITRF2020 strategy: stacking of all technique time series all together ==> Adding extended time series is easy to handle Motivation: 1. Errors in ITRF station coordinates are more and more amplified as they are extrapolated after the end of the ITRF input data; 2. ITRF stations subject to equipment changes or earthquakes posterior to the end of the ITRF input data cannot be used anymore as reference frame stations; 3. Most of the TCs regularly update their own realizations of the ITRF; 4. ==> Increase ITRF2020 lifetime and may postpone the need for the next version of the ITRF; 5. The scale agreement between SLR and VLBI is now at the level of 1 mm 6. ITRF origin and scale are now stabilized (see next slide) 7. ==> This will simplify the life of a number of users, with no datum change in their applications Altamimi et al., IGS Workshop 2024, Bern, Switzerland
Transformation Parameters: From ITRF2020 to past ITRFs Transformation parameters from ITRF2020 to past ITRFs at Epoch 2015.0 ------------------------------------------------------------------------------- SOLUTION Tx Ty Tz UNITS----------> mm mm mm . . . . . . . RATES Tx Ty Tz UNITS----------> mm/y mm/y mm/y ppb/y .001"/y .001"/y .001"/y -------------------------------------------------------------------------------- ITRF2014 -1.4 -0.9 1.4 -0.42 0.00 0.00 0.00 rates 0.0 -0.1 0.2 0.00 0.00 0.00 0.00 ITRF2008 0.2 1.0 3.3 -0.29 0.00 0.00 0.00 rates 0.0 -0.1 0.1 0.03 0.00 0.00 0.00 ITRF2005 2.7 0.1 -1.4 0.65 0.00 0.00 0.00 rates 0.3 -0.1 0.1 0.03 0.00 0.00 0.00 ITRF2000 -0.2 0.8 -34.2 2.25 0.00 0.00 0.00 rates 0.1 0.0 -1.7 0.11 0.00 0.00 0.00 D Rx Ry Rz ppb .001" .001" .001" D Rx Ry Rz Altamimi et al., IGS Workshop 2024, Bern, Switzerland
ITRF2020 Update Specifications Same analysis strategy as for ITRF2020: Accumulate the full 4 technique time series all together, adding local ties and co-motion constraints Plan to preserve the frame and seasonal signal defining parameters in origin, scale, and orientation ITRF2020 updates will be delivered using the same file format as ITRF2020 IAG TCs used the same models and strategy as for their contribution to the ITRF2020 Analysis is still ongoing Altamimi et al., IGS Workshop 2024, Bern, Switzerland
Sites ITRF2020 Update 1 Altamimi et al., IGS Workshop 2024, Bern, Switzerland
ITRF2020 Update 1: GNSS Sites 1159 sites 1350 stations 3221 discontinuities Altamimi et al., IGS Workshop 2024, Bern, Switzerland
Some preliminary results using the extended data Altamimi et al., IGS Workshop 2024, Bern, Switzerland
ILRS/SLR intrinsic (ITRF2020 input data) origin & scale Altamimi et al., IGS Workshop 2024, Bern, Switzerland
ILRS/SLR intrinsic origin & scale with extension SLR Origin & scale accuracy at 2015.0 below 1 mm and scale stability at the level of 0.1 mm/yr Altamimi et al., IGS Workshop 2024, Bern, Switzerland
IGS/GNSS origin & scale wrt ITRF2020 Altamimi et al., IGS Workshop 2024, Bern, Switzerland
IDS/DORIS origin & scale wrt ITRF2020 with extension Altamimi et al., IGS Workshop 2024, Bern, Switzerland
IVS/VLBI Intrinsic Scale (ITRF2020 Sessions) Extension Red: Selected VLBI Sessions (convex hull volume 1019m3) Altamimi et al., IGS Workshop 2024, Bern, Switzerland
IVS/VLBI Intrinsic Scale (ITRF2020 Sessions + Extension) Extension ==> D = + 0.35 ppb at epoch 2015.0, 0.025 ppb/yr Altamimi et al., IGS Workshop 2024, Bern, Switzerland
Conclusion No major issue so far with technique extended data Stability of SLR/ILRS origin and scale, with the extension, is at the level of or better than 0.1 mm/yr The IVS/VLBI scale comes back to normal , after the extension, starting at 2021.0 Expected release date : summer 2024! There will be no changes to the defining parameters of the frame and seasonal signals (origin, scale, orientation) between ITRF2020 and its 1stupdate Proposed name: ITRF2020-u2023 Altamimi et al., IGS Workshop 2024, Bern, Switzerland
